Thursday, May 24, 2012

Calcium booster pills 'raise risk of heart attack and could do more harm than good'

Taking calcium supplements can push up the risk of a heart attack, warn researchers.  They claim the safety of the tablets is 'coming under increasing scrutiny' as they could be doing more harm than good.

Hundreds of thousands of women take  the boosters as they are recommended for strengthening bones against osteoporosis.

But, according to the study, the supplements can no longer be seen as a low-cost panacea against thinning bones.  Instead, the scientists suggest, people should eat more calcium-rich foods like milk, cheese and green, leafy vegetables.

They found that those using calcium boosters, with no other supplements, had double the risk of a cardiac attack than others who did not take them.

Researchers looked at records for 24,000 people in Germany aged 35 to 64 taking part in a nutrition research project in the 1990s.

Their diet was analysed and they were asked if they had taken vitamin or mineral supplements in the previous month.

The volunteers were tracked for 11 years, during which there were 354 heart attacks, 260 strokes and 267 associated deaths.

Those taking any supplements, including calcium, were found to be 86 per cent more likely to have a heart attack than those who did not take any. But the risk for those taking only calcium was even higher.

Researchers claim the tablets have a potentially harmful 'flooding' effect on the levels of the mineral in the blood, it was reported in the medical journal Heart. Calcium in food or drink is spread through the day and so absorbed slowly.

In the study, Professors Ian Reid and Mark Bolland, at the University of Auckland, New Zealand, said people should be discouraged from taking the boosters. 

It was also wrong to see them as natural  as they do 'not reproduce the same effects as calcium in food', they added.

The National Osteoporosis Society said there was not enough evidence to say the supplements trigger heart problems.

The Food Standards Agency advises adults to have 700mg of calcium a day in their diet.


Feeling hormonal? How serious cycling could be playing havoc with male reproductive health

Male cycling enthusiasts may have more to worry about than saddle sores and road safety, after a study found the sport can play havoc with their fertility.

Researchers at UCLA School of Nursing found serious cyclists - rather than the recreational rider - could experience hormonal imbalances that could affect their reproductive health.

They found keen bikers had more than double the amount of estradiol in their blood compared to triathletes and other sport enthusiasts.

Estradiol is a form of estrogen and, in males, is produced as an active metabolic product of testosterone.

Possible conditions associated with elevated estrogen in males include gynecomastia, a condition that may result in the loss of pubic hair and enlarged breast tissue.

Study author assistant professor Leah FitzGerald, said: 'Although preliminary, these findings warrant further investigation to determine if specific types of exercise may be associated with altered sex-hormone levels in men that could affect general health and reproductive well-being.' 

Most research studying the effects of exercise on reproductive health has focused on female athletes; there have been few studies that have looked at male endurance-trained athletes.

The UCLA study explored associations between exercise intensity and circulating levels of reproductive hormones in both serious leisure athletes and recreational athletes.

The researchers divided 107 healthy male study subjects (ages 18 to 60) into three groups: 16 triathletes, 46 cyclists and 45 recreational athletes.

Participants completed the International Physical Assessment Questionnaire to provide an objective estimate of time they spent participating in different levels of physical activity and inactivity during the previous week.

Blood samples were then collected from each participant to measure total testosterone, estradiol, cortisol, interleukin-6 and other hormones.

Plasma estradiol concentrations were more than two times higher in the cyclists than in the triathletes and recreational athletes, and total testosterone levels were about 50 percent higher in cyclists than in the recreational athletes.

'Plasma estradiol and testosterone levels were significantly elevated in serious leisure male cyclists, a finding not previously reported in any type of male athlete,' said Leah FitzGerald.

The study has been published in the European Journal of Applied Physiology.


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